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Mercedes 300D Suggestions

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  • Mr_ShiftrightMr_Shiftright Member Posts: 64,481
    That's a lot of miles. And it is not "common" for ANY car to go 400K--that is the extreme end of the bell curve and statistically unlikely. So don't count on that any more than you should count on living to be 105----you might, but most don't :P

    I'd say the average life of a 300 series diesel is about 250,000 with good care and presuming no engine/trans replacements or major restoration (after all, you can keep any car running forever if you pay enough). If you don't think so, go to a wrecking yard and read odometers. What better way to get some good data?

    So you are buying a car in the...okay, let's be generous...last third of its life.

    What do I think it's REALLY worth? About $6,500. What is the most you should pay? If you really have to have it, and it checks out GREAT, and you haven't seen anything nicer, then maybe up to $7,500. After that, you are over the market and on your own...your call.

    Remember---whatever gets you INTO a car cheap at the time you buy will come back to haunt you if you want to unload it. So if you don't like the car in 6 months, it'll have over 200K on it which makes it a hard sell for top dollar.

    If this car had 75,000 miles it could bring $8,500 or better, say from a dealer's lot with a financing provision.

    It does look clean, though, I'll say that. I don't know about the guy's story though. you could do a CARFAX report and check his mileage claims over the last 4 years. And "highway" miles is a meaningless term in some ways. Miles are miles when it comes to market value.
  • brakeengrbrakeengr Member Posts: 98
    I just can't seem to stop this fuel leak at the main fuel filter housing on my '82 300D turbo.
    I changed the fuel filter- replaced the aftermarket with a MB from dealer.
    I put a new metal seal between housing and the bolt (that screws into the filter).
    Also, put a new rubber seal on the hollow bolt that screws into the filter (this rubber seal is in the stem of the main bolt).
    I bled the air by loosening the hollow bolt that goes out of the housing.
    (Haven't touched the bolt that comes back into the housing).
    Still have fuel leaking from under the top of the main bolt that screws into the fuel filter. after driving 3 miles.
    I don't remember seeing any leaks before I changed the fuel filter. And I can see now the difference in the diesel consumption- the gauge needle drops down faster.
    Is there anything else I should look at? It was supposed to be a simple fuel filter change!!
    Thanks for any help.
  • Mr_ShiftrightMr_Shiftright Member Posts: 64,481
    That's weird. Maybe you can find a neophrene seal that will fit around the bolt. do you think you might have tightened down too hard?
  • brakeengrbrakeengr Member Posts: 98
    No, I don't think I tightened too hard. With the old seal, i did tighten hard, thinking that would help. When it didn't, I got a new seal and noticed it was thicker than the old one, and it's brass- so I knew it was soft; hence took extra care not to tighten too hard.
    Maybe I should run a very fine sand paper on the housing surface where the metal seal sits?
    I cannot think of anything else, and I wanted to make sure there wasn't any other "trick" associated with changing the fuel filter. Is there anything else I need to be aware of?
  • riverviewriverview Member Posts: 1
    I have a 1981 300d it is not a turbo. I am having a problem with the air conditioner. What could be making the fuse for the air conditioner keep blowing. I have had to change it several times.
  • samgm2samgm2 Member Posts: 14
    I have a 1985 300D that maybe having problems with the climate control switch (perhaps its something else). The usually does not come on. I believed the problem was in the climate control switch and took it apart and tested all the relays by applying 12 V to the circuit board as necessary and what I could of the switches. I also cleaned the contacts. Everything seemed to be in order with a cursory check with a multimeter but still no go.

    I do get heat ( not that I want it in the summer, but only as a result of natural air flow if the vent is open). No AC, no blower, no defrost.

    Anyone have a clue what direction I can take now. The maintainance manual refers to a diagnostic tool that I don't have for trouble shooting the system.

    Sam.
  • 300cdveggie300cdveggie Member Posts: 15
    here's a website that I found recently that should help.

    http://boostnbenz.1baddsm.com/DIY/
  • brakeengrbrakeengr Member Posts: 98
    Well- this problem is now solved. The metal washer needed to seat better on the housing. I sanded the housing top lightly with very fine sand paper (waterpaper) to get rid of the little build up and a very small protrusion; reseated the washer and hollow bolt- voila! drove 50 miles without fuel leakage. I guess every small bit must fit properly!
  • jnicoljnicol Member Posts: 5
    I took my 82 330D in and had the transmission flushed. It was running great. Went to pick up the car and it wouldn't start. It sputtered and blew a cloud of black smoke and then just turned over and over. Brought my 300SD to it and tried jumping it. I fiddled for about an hour looking for vacuum leaks and whatever I could see. Oddly after about an hour of cranking on and off it started and ran great. I drove it home, turned it off, restarted it no problem and left it over night. The next morning the same problem.

    I changed the fuel filters, reprimed it, pulled the glow plugs and checked resistance all about 1 ohm, took the glow plug relay out of the 300SD and popped it in - still won't start. Took a rag and dipped it in gasoline and put it inside the air cleaner (outside of the filter - eventually got it going - it ran great. Next morning it won't start.

    The glow plug light comes on for about 3 seconds and goes out normally. There is no smoke at all coming out of the exhaust while it's cranking.

    I'm out of ideas. Could the transmission shop have knocked something loose that's causing this problem? Could it be a bad fuel pump, injector pump...? How can I tell? Any help or suggestions will be most welcome.
  • Mr_ShiftrightMr_Shiftright Member Posts: 64,481
    Oh your glow plug should stay on longer than that on a cold engine. I think you need to replace the glow plugs if in fact the engine runs great but won't start. You should replace the glow plugs every 2-3 years anyway.
  • levlcrsclasicslevlcrsclasics Member Posts: 1
    I had the same problem with my 83 300D. Check the black rectangle shaped box that is mounted on the drivers side from fender under the hood, should be located near the front of the fender. There is a small metal link(fuse) that is held in place by 2 screws. This is a fuse to the glow plugs. The time I had that problem, this was the solution, if it blown, you will be able to see this right away. BTW you will need to remove the cover on the box to see the fuse.

    Ken Sharpe :surprise:
  • Mr_ShiftrightMr_Shiftright Member Posts: 64,481
    Yeah I was wondering about that fuse link (80 amp?) but then I wasn't sure if the glow plug light would even light.

    But anyway, good idea to check that...although blowing 80 amps is a kind of scary thought...how did THAT happen?

    I have a test you might try but you have to be very careful...you can activate just ONE glow plug with a battery jumper cable and see if the engine kicks off...but you have to be very careful not to ground the battery cable to anything metal except the tip of the plug....tricky...I used to do this test by wrapping very heavy gauge wire around the glow plug and then attaching the jumper cable to that, maybe one foot out of harm's way.
  • brakeengrbrakeengr Member Posts: 98
    What kind of mileage is expected for a 300D? I am getting 25mpg on the highway with my 82 300D turbo. I was expecting around 28. Anyway to improve it?
  • Mr_ShiftrightMr_Shiftright Member Posts: 64,481
    25 is pretty darn good, you can't do much better than that unless you want to start driving in a very silly way. Remember you have a very heavy car shaped like a brick--you can't fight aerodynamics unless you want to do something radical to the car or drive more slowly and cautiously.

    I suppose you could inflate your tires more and carry less fuel and get a 4-wheel alignment---all those things might....MIGHT...gain you 1 mpg.
  • brakeengrbrakeengr Member Posts: 98
    Just trying to squeeze every little mile- at todays gas prices!! I guess I should be happy with 25. I drive normal, and absolutely love the feel of the car.
    I did one very very stupid thing recently, though. While changing fuel filters and checking for leaks, I did not latch the hood down tight, and drove in my sub- Well, the wind opened up the hood, and one hinge got twisted a tiny weeny bit, and so now when I close the hood, there is a slight intereference on the passenger side near the windshield side.
    Would a body shop be able to set it straight?
  • Mr_ShiftrightMr_Shiftright Member Posts: 64,481
    Yeah, a body shop might be able to help you---it rather depends on what got bent and where.

    As for better MPG, you might also try synthetic oil, although I'm a bit wary recommending synthetic oil on a car that is very old.
  • brakeengrbrakeengr Member Posts: 98
    At my last oil change- about 700 miles ago- I did put Pennzoil synthetic and dumped a bottle of the Lucas cleaner in the tank. I can feel the difference- it runs much smoother and I think the diesel noise inside the car is lower. You can just get that feeling of a well oiled powerful machine purring along!
    Yesterday my driver side window stopped working, Previously, for a rear window it was the fuse- I'll check fuse again for this one also, but do the switches or motor have a tendency to go bad?
  • jnicoljnicol Member Posts: 5
    Thanks for the good advice, everyone. I have a followup question or two.

    1. No one commented on the glow plug resistance. Shouldn't I be able to spot a bad glow plug in this way? I'm wondering if it might be a bad wiring harness also. I'm still wondering if something may have happened at the trans shop. I checked the 80 amp fuse and it's intact.
    2. Could clogged injectors or bad fuel pump cause this problem starting, yet allow the engine to run okay once it gets going?
    3. Should I use a glow plug reamer when I change the plugs?

    Thanks all!!!
  • shibbiedshibbied Member Posts: 3
    Hey I got a 1976 Mercedes and im trying to change alternators..But i cant get to the top nut to loosen it so i can get the belt to loosen up.. Anyone have ne suggestions on how to do that??
  • shibbiedshibbied Member Posts: 3
    Ok i got the alternator off and it is stuck under the hood like a mouse in a trap but does anyone have ne idea how i can get it out... From what we can see is we are going to haft to take out the air compressor to be able to fit it through the top..But to get that off it is looking like we are going to haft to take almost everything off to just get it out... So if you got ne ideas on what to do or know how plz tell me...TY!!!!
  • Mr_ShiftrightMr_Shiftright Member Posts: 64,481
    Could be a switch, which you can pop out and bypass as a test...also the window regulators tend to break in half, very common.
  • shibbiedshibbied Member Posts: 3
    Ok me and dad said forget it on the alternator and put it back in.. now car wont start.. we have been checking things and what we can tell is that my glow plug is not going off at all... As soon as i put key into ignition the plug is on.. when it shouldn't be on till i turn key to right about 2 clicks or whatever it is... Can anyone tell me how to get it to go off and only come on when it is supposed to??? Or do i got to buy a new plug or whatever?
  • jnicoljnicol Member Posts: 5
    The consensus seemed to be glow plugs. I replaced them today and it still won't start. You'll remember that when I had it running (after much jumping and cranking and putting a gas soaked rag around the air cleaner element) it ran great. It restarted when warm, but wouldn't run the next day. I'll repost my earlier questions, perhaps someone can comment or has an idea what to check next.

    1. No one commented on the glow plug resistance. Shouldn't I be able to spot a bad glow plug in this way? I'm wondering if it might be a bad wiring harness also. I'm still wondering if something may have happened at the trans shop. I checked the 80 amp fuse and it's intact.
    2. Could clogged injectors or bad fuel pump cause this problem starting, yet allow the engine to run okay once it gets going?
    3. Should I use a glow plug reamer when I change the plugs?

    Thanks all!!!
  • Mr_ShiftrightMr_Shiftright Member Posts: 64,481
    I still think you have a glow plug issue of some type.
  • brakeengrbrakeengr Member Posts: 98
    I had a similar problem on my 82 300D couple of years back. I put in new battery thinking it had gotten old- it then started, but after running sometime and overnight, again would not start. I replaced alternator, thinking it wasn't charging the battery- no luck.
    Finally, took it in to a dealer- problem was the glow plug module. What was happening was that it was draining power even while driving, when it was not supposed to- i.e. glow plug(s) was/ were always draining power- hence, power consumption was more than the alternator could generate.
    I think they also replaced some glow plugs at that time.
    If you can get it running by jump starting/ rags/ whatever- check your battery charging. If it seems that it is not charging, problem could in fact be the glow plug module; not battery or alternator.
    Good Luck!
  • babaobabao Member Posts: 1
    I have an 84 300sd that's never given me any problems, until one day, toward the end of a (somewhat routine) 250 mile drive, it started losing power, then just died, as if out of fuel. It was hard to start again, but did. Idled pretty ok, then drove for 5 minutes, & did it again. It seemed to be able to do this over & over, but I lost interest in the 10 minute wait in between each start. I've been away, so haven't gotten a good look. I'm going to visit it soon. Any ideas where I should start? Thanks
  • jnicoljnicol Member Posts: 5
    Thanks for the advice. The battery has been on the charger so I have a full charge to try and start it. I pulled the glow plug module from my other Mercedes and popped it into the 300D, but no go. Mr. Shiftright still thinks it's glow plugs. I think I'm going to have it towed to a shop. This has got to be simple. It started and ran when it went into the trans shop. The trans guy started it and test drove it. Suddenly it's not starting. It has shown it can run like a bear once it's running, but otherwise it appears dead - no smoke or exhaust of any kind while it's cranking.

    As for mysterious power drains... my battery kept discharging over night. One day I'm standing next to the car while it's turned off and I hear the antenna trying to go down. It repeated this evevery minute or two. I disconnected the electical plug to the antenna and the problem was solved.
  • Mr_ShiftrightMr_Shiftright Member Posts: 64,481
    Well the only other thing I can think of is that you are way down on compression on one cylinder. A diesel starts with compression and fuel and the glow plugs. So if you are confident the glow plugs have been eliminated, you either have a fuel issue at cold start or low compression.

    On a warm engine, compression will be better.

    Have the valves ever been adjusted on this car?
  • jnicoljnicol Member Posts: 5
    The valves haven't been adjusted in a couple of years. I've never had the valve cover off. Is this something I can do myself? Looks like the valve cover needsd a special kind of allen-type wrench.

    John
  • Mr_ShiftrightMr_Shiftright Member Posts: 64,481
    You also need a special tool to turn the adjusting screw on the valve rocker...a kind of "crow's foot".
  • grurkagrurka Member Posts: 2
    I have a 82 and 85 300SD with new air conditioning compressors. Over the past year or so the AC seemed to work intermittently. It would work fine when the car first started for an hour or so, but even in the hot summer sun, the fan would not kick in. You could feel the AC cold air in the vents on the dash. When you hit the EC button, the fan would blow the cool air through the vents, but since the AC compressor is not engaged when the EC button is depressed, the cool air becomes warm quickly. There appears to be three components 1) the fan switch, 2) the center piano keys and 3) on the left, the temp. wheel. Has anyone had this problem? This is a costly operation to replace all three controls. Any hlep would be greatly appreciated.
  • Mr_ShiftrightMr_Shiftright Member Posts: 64,481
    You might find this helpful:

    http://boostnbenz.1baddsm.com/DIY/Climate/
  • grurkagrurka Member Posts: 2
    Mr. Shiftright - thanks for the great information. The fan on my Benz does not go on during minimum or maximum or defrost. the air conditioning compressor does run. Cool air gets into the vent, but the fan does not go on. Trying to press the control buttons or turning the temp wheel or fan buttons does not engage the fan. BUT when I start the car and put the AC button on, it works fine for an hour or so. Then it will shut off on its own, the car will then get hot and when you are just about ready to pass out, it may go on again on its own. I have found a few pieces of sticky foam that has come through the vent. Any thoughts? Thanks Gene
  • Mr_ShiftrightMr_Shiftright Member Posts: 64,481
    Gee I don't know what to say. The climate controls on the 300D is so tempermental and known for misbehavior, that one would have to suspect the control unit.
  • tmrbojtmrboj Member Posts: 1
    Hello, I have a 83 300d Turbo Diesel. I need to take off the bracket that holds the e-brake pedal on to the body to get to some body rot where the hinge is that holds up the hood.... I've been trying this all morning and I cant figure out how to get to the bolts, IE take off the pedal to get behind it to get to the screws... ANY THOUGHTS ARE WELCOME...
  • labralabra Member Posts: 1
    Hello. I have a 1985 300d turbo deisel. Both directionals do not work. I have replaced the fuse and they still do not work. The hazards do work fine though. I just bought the car and it has 125,000 original miles. I just want to know what I have to do maintain the car.
  • Mr_ShiftrightMr_Shiftright Member Posts: 64,481
    Try new bulbs or at least pop them out and see if they are corroded. Also you can track down the directional signal flasher (relay) which I don't think is the same one as the hazard relay....not sure about this....
  • tneuhaustneuhaus Member Posts: 1
    I had this problem with my heat in my 84 300d. We took out the control box and found some bad solder joints in the box. It took about 15 min to fix. Since then it has worked great.
  • mercerzamercerza Member Posts: 3
    The car starts up cold runs great no problems and every once in a while it wont do anything. It doesn't over heat, I tighten the battery cables, even tried a jump start.

    There is nothing when this happens, just a low push of air sound maybe in the front left (sitting in the driver seat).

    If it sits a half hour to 45 mins it starts again no problems for a while after that.

    Any Ideas?
  • Mr_ShiftrightMr_Shiftright Member Posts: 64,481
    Sounds like a bad starter or starter relay
  • pistonheadpistonhead Member Posts: 3
    I own a 1985 300 SD mercedes. I have replaced the climate control unit for the second time, and something is spiking the current and blowing the climate control unit, without blowing a fuse.

    Any ideas about what would be the problem?

    Pistonhead
  • Mr_ShiftrightMr_Shiftright Member Posts: 64,481
    Perhaps the wrong size fuse? Really that shouldn't be possible if the fuse is correct. Are these rebuilt units? Who did the wiring? Maybe someone somewhere at some time wired it to an unfused circuit.
  • mercerzamercerza Member Posts: 3
    Do you think it could be the glow plugs? How many glow plugs does it have? Are they simple to replace?
  • Mr_ShiftrightMr_Shiftright Member Posts: 64,481
    Usually glow plugs are only an issue with a cold engine. Hot start problems suggest to me a weak battery (after all, this is a compression-ignition engine, so it has to SPIN).

    There is one glow plug for each cylinder. They are a bit awkward to get out...best done with a 3/8" extension, a u-joint and a deep socket...15-30 minute job at most.
  • pistonheadpistonhead Member Posts: 3
    Fuses are correct. Both units were rebuilt. by Programa. Should I suspect two that failed back to back?
  • Mr_ShiftrightMr_Shiftright Member Posts: 64,481
    Well, is there visible damage or ??? What evidence is there for the alleged voltage surge?
  • pistonheadpistonhead Member Posts: 3
    No damage visually. The chips in the climate control unit have apparently failed and rendered the device inoperative. The unit worked for 2 days and then failed, just as unit before it. I am stumped that two different units have failed in a similar manner.
  • Mr_ShiftrightMr_Shiftright Member Posts: 64,481
    very weird indeed...one would think the fuse would HAVE to protect it.
  • cfmnhcfmnh Member Posts: 1
    I'm a "newbie", and hope I'm posting in the right place. Model is a Mercedes 1982 300D.The Fuse for blower fans and the ac clutch is rated at 16 amps, but draws 18amps! The fans only draw 2 amps, but when AC or defrost is selected current jumps to 18amps. The fuse gets hot! The AC clutch works OK, AC seems to work, but if left on very long blows the fuse. I have a hard to read Haynes manual with wiring diagrams that tests my eyesight... What to do next?
  • tallgirltallgirl Member Posts: 4
    Nothing in my turn signal system is working. Instrument panel arrows, front and back blinkers...nothing. I have eliminated the fuse as a problem (all the other stuff on the #12 works, I'm at my limit). What else could it be? Swithes? Relays? I have no idea. It's gonn'a have to be sometin' real simple for me to fix. I will pray until the answer is revealed.
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